5.1 Classifying Rocks

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Vocabulary

texture-the look or feel of a rocks surface
grains-a particle or mineral that give rocks their texture
Igneous rock-a rock that was once magma and cooled
sedimentary rock-another type of rock or the remains plants or animals pressed together
metamorphic rock-A kind of rock that forms when another rock is changed by heat pressure or chemical reactions

Outline

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Classifying rocks

• How geologists classify rocks
  • scientist determine where the rock was formed or use texture
• Texture
  • color does not provide much information to identify a rock
    • this is why scientists use texture
• Grain size
  • rocks have grains in different sizes
• Grain shape
  • Grains can come in different shapes
• Grain pattern
  • the grains of a rock forms in different patterns
• no visible grain
  • grains can be invisible
• Mineral composition
• Origin
  • There majar types of rock, igneous, sedimentary, and metamorphic